The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform
K. Yoshimura - One of the best experts on this subject based on the ideXlab platform.
-
A semi-Lagrangian advection scheme for Radioactive Tracers in the NCEP Regional Spectral Model (RSM)
Geoscientific Model Development, 2015Co-Authors: E. C. Chang, K. YoshimuraAbstract:Abstract. In this study, the non-iteration dimensional-split semi-Lagrangian (NDSL) advection scheme is applied to the National Centers for Environmental Prediction (NCEP) Regional Spectral Model (RSM) to alleviate the Gibbs phenomenon. The Gibbs phenomenon is a problem wherein negative values of positive-definite quantities (e.g., moisture and Tracers) are generated by the spectral space transformation in a spectral model system. To solve this problem, the spectral prognostic specific humidity and Radioactive tracer advection scheme is replaced by the NDSL advection scheme, which considers advection of Tracers in a grid system without spectral space transformations. A regional version of the NDSL is developed in this study and is applied to the RSM. Idealized experiments show that the regional version of the NDSL is successful. The model runs for an actual case study suggest that the NDSL can successfully advect Radioactive Tracers (iodine-131 and cesium-137) without noise from the Gibbs phenomenon. The NDSL can also remove negative specific humidity values produced in spectral calculations without losing detailed features.
-
A semi-Lagrangian advection scheme for Radioactive Tracers in a regional spectral model
2015Co-Authors: E. C. Chang, K. YoshimuraAbstract:Abstract. In this study, the non-iteration dimensional-split semi-Lagrangian (NDSL) advection scheme is applied to the National Centers for Environmental Prediction (NCEP) regional spectral model (RSM) to alleviate the Gibbs phenomenon. The Gibbs phenomenon is a problem wherein negative values of positive-definite quantities (e.g., moisture and Tracers) are generated by the spectral space transformation in a spectral model system. To solve this problem, the spectral prognostic specific humidity and Radioactive tracer advection scheme is replaced by the NDSL advection scheme, which considers advection of Tracers in a grid system without spectral space transformations. A regional version of the NDSL is developed in this study and is applied to the RSM. Idealized experiments show that the regional version of the NDSL is successful. The model runs for an actual case study suggest that the NDSL can successfully advect Radioactive Tracers (iodine-131 and cesium-137) without noise from the Gibbs phenomenon. The NDSL can also remove negative specific humidity values produced in spectral calculations without losing detailed features.
E. C. Chang - One of the best experts on this subject based on the ideXlab platform.
-
A semi-Lagrangian advection scheme for Radioactive Tracers in the NCEP Regional Spectral Model (RSM)
Geoscientific Model Development, 2015Co-Authors: E. C. Chang, K. YoshimuraAbstract:Abstract. In this study, the non-iteration dimensional-split semi-Lagrangian (NDSL) advection scheme is applied to the National Centers for Environmental Prediction (NCEP) Regional Spectral Model (RSM) to alleviate the Gibbs phenomenon. The Gibbs phenomenon is a problem wherein negative values of positive-definite quantities (e.g., moisture and Tracers) are generated by the spectral space transformation in a spectral model system. To solve this problem, the spectral prognostic specific humidity and Radioactive tracer advection scheme is replaced by the NDSL advection scheme, which considers advection of Tracers in a grid system without spectral space transformations. A regional version of the NDSL is developed in this study and is applied to the RSM. Idealized experiments show that the regional version of the NDSL is successful. The model runs for an actual case study suggest that the NDSL can successfully advect Radioactive Tracers (iodine-131 and cesium-137) without noise from the Gibbs phenomenon. The NDSL can also remove negative specific humidity values produced in spectral calculations without losing detailed features.
-
A semi-Lagrangian advection scheme for Radioactive Tracers in a regional spectral model
2015Co-Authors: E. C. Chang, K. YoshimuraAbstract:Abstract. In this study, the non-iteration dimensional-split semi-Lagrangian (NDSL) advection scheme is applied to the National Centers for Environmental Prediction (NCEP) regional spectral model (RSM) to alleviate the Gibbs phenomenon. The Gibbs phenomenon is a problem wherein negative values of positive-definite quantities (e.g., moisture and Tracers) are generated by the spectral space transformation in a spectral model system. To solve this problem, the spectral prognostic specific humidity and Radioactive tracer advection scheme is replaced by the NDSL advection scheme, which considers advection of Tracers in a grid system without spectral space transformations. A regional version of the NDSL is developed in this study and is applied to the RSM. Idealized experiments show that the regional version of the NDSL is successful. The model runs for an actual case study suggest that the NDSL can successfully advect Radioactive Tracers (iodine-131 and cesium-137) without noise from the Gibbs phenomenon. The NDSL can also remove negative specific humidity values produced in spectral calculations without losing detailed features.
Freek J Beekman - One of the best experts on this subject based on the ideXlab platform.
-
Introduction to the physics of molecular imaging with Radioactive Tracers in small animals.
Journal of cellular biochemistry. Supplement, 2002Co-Authors: Michael A King, P Hendrik Pretorius, Troy Farncombe, Freek J BeekmanAbstract:Recent advances have greatly enhanced the three-dimensional (3D) imaging of Radioactive Tracers in living animals. this article introduces the physics of imaging behind the imaging methods. The article first discusses the selection of the radiation emitted from the tracer and then the process of tomographic reconstruction or how 3D images are made from imaging around the outside of the animal. The technique of single photon emission computed tomography (SPECT) in which the detection of one X-ray or gamma ray at a time is employed for image formation is then described. Finally, positron emission tomography (PET) which relies on the simultaneous detection of the pair of gamma-rays formed when the positron annihilates is presented.
-
introduction to the physics of molecular imaging with Radioactive Tracers in small animals
Journal of Cellular Biochemistry, 2002Co-Authors: Michael A King, Troy Farncombe, Hendrik P Pretorius, Freek J BeekmanAbstract:Recent advances have greatly enhanced the three-dimensional (3D) imaging of Radioactive Tracers in living animals. this article introduces the physics of imaging behind the imaging methods. The article first discusses the selection of the radiation emitted from the tracer and then the process of tomographic reconstruction or how 3D images are made from imaging around the outside of the animal. The technique of single photon emission computed tomography (SPECT) in which the detection of one X-ray or gamma ray at a time is employed for image formation is then described. Finally, positron emission tomography (PET) which relies on the simultaneous detection of the pair of gamma-rays formed when the positron annihilates is presented. J. Cell. Biochem. Suppl. 39: 221–230, 2002. © 2002 Wiley-Liss, Inc.
Bernd Meyer - One of the best experts on this subject based on the ideXlab platform.
-
Determination of residence time distributions in different high pressure gasification processes by Radioactive Tracers
International Journal of Hydrogen Energy, 2014Co-Authors: Andreas Ortwein, Albert Zeuner, Thorsten Jentsch, Rene Dr.-ing. Zeißler, Peter Dr. Seifert, Holger Schlichting, Bernd MeyerAbstract:Abstract High-Pressure Partial Oxidation is a key technology for the usage of flare gases and heavy oil residues. At the test plant of TU Bergakademie Freiberg, it is possible to gasify different gaseous and liquid fuels at pressures up to 100 bar (g). Information on residence time distributions can be gained by using Radioactive Tracers. The results of measurements for different reactor geometries and feedstocks will be discussed in this paper. Results of Radioactive residence time measurements depend strongly on reactor geometry and require different evaluation methods.
Michael A King - One of the best experts on this subject based on the ideXlab platform.
-
Introduction to the physics of molecular imaging with Radioactive Tracers in small animals.
Journal of cellular biochemistry. Supplement, 2002Co-Authors: Michael A King, P Hendrik Pretorius, Troy Farncombe, Freek J BeekmanAbstract:Recent advances have greatly enhanced the three-dimensional (3D) imaging of Radioactive Tracers in living animals. this article introduces the physics of imaging behind the imaging methods. The article first discusses the selection of the radiation emitted from the tracer and then the process of tomographic reconstruction or how 3D images are made from imaging around the outside of the animal. The technique of single photon emission computed tomography (SPECT) in which the detection of one X-ray or gamma ray at a time is employed for image formation is then described. Finally, positron emission tomography (PET) which relies on the simultaneous detection of the pair of gamma-rays formed when the positron annihilates is presented.
-
introduction to the physics of molecular imaging with Radioactive Tracers in small animals
Journal of Cellular Biochemistry, 2002Co-Authors: Michael A King, Troy Farncombe, Hendrik P Pretorius, Freek J BeekmanAbstract:Recent advances have greatly enhanced the three-dimensional (3D) imaging of Radioactive Tracers in living animals. this article introduces the physics of imaging behind the imaging methods. The article first discusses the selection of the radiation emitted from the tracer and then the process of tomographic reconstruction or how 3D images are made from imaging around the outside of the animal. The technique of single photon emission computed tomography (SPECT) in which the detection of one X-ray or gamma ray at a time is employed for image formation is then described. Finally, positron emission tomography (PET) which relies on the simultaneous detection of the pair of gamma-rays formed when the positron annihilates is presented. J. Cell. Biochem. Suppl. 39: 221–230, 2002. © 2002 Wiley-Liss, Inc.
